(1) Field of the Invention
The present invention generally relates to the propulsion and control system of a torpedo. The present design is simpler, has fewer moving components and is more efficient than my previous inventions, Variable Speed Reducing and Torque Transmitting System, U.S. Pat. No. 4,411,172 dated Oct. 25, 1983; U.S. Pat. No. 4,392,443 dated July 12, 1983, Electro-Pneumatic Hydraulic Control Systems; and U.S. Pat. No. 4,360,348 dated Nov. 23, 1982, Underwater Vehicle Porting System. All three applications were filed Feb. 20, 1981.
(2) Description of the Prior Art
In my previous inventions, supra, each of two impellers is driven by one of two sets of four satellite rollers rotating at relatively high speeds. The two sets of rollers are driven by a single rotating input. The net speed of each set is approximately four time the speed of the input member. The control of each impeller is independent of the other such that a dual control system is required. To increase or decrease the speed of the impellers in unison, positive or negative hydraulic pressure is required at both controls. To increase the speed of one impeller while decreasing the other requires positive pressure at one control and negative pressure at the other. There is some ambiguity when switching the hydraulic supply because of the possibility of overshooting positive or negative pressure which can result in both being on simultaneously. This condition tends to deteriorate the reserve available supply of hydraulic fluid.
The porting system is also dual control and the previously mentioned ambiguity is a source of drain on the reserve available supply of hydraulic fluid in much the same fashion. Furthermore, the ports are not strategically oriented. They are located perpendicular to seawater flow in an area where flow pressure is only slightly reduced.
The electrical motor with its required brushes is necessarily located remote from the impellers. Valuable space is sacrificed and the required long shaft extension for driving both sets of satellite rollers can be a source of dynamic instabilities.